package com.heima.wemedia.gateway.filter;


import com.heima.wemedia.gateway.util.AppJwtUtil;
import io.jsonwebtoken.Claims;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang.StringUtils;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.Ordered;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

//这段代码定义了一个名为AuthorizeFilter的全局过滤器，用于Spring Cloud Gateway中
//该过滤器的主要功能是对每个通过网关的请求进行身份验证
@Component
@Slf4j
public class AuthorizeFilter implements Ordered, GlobalFilter {

	//首先从ServerWebExchange中获取请求和响应对象，这两个对象分别代表了HTTP请求和响应
	@Override
	public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
		//1.获取request和response对象
		ServerHttpRequest request = exchange.getRequest();
		ServerHttpResponse response = exchange.getResponse();

		//2.判断是否是登录,如果是登录请求，则直接放行，不进行身份验证
		if (request.getURI().getPath().contains("/login")) {
			//放行
			return chain.filter(exchange);
		}

		//3.获取token,从HTTP请求的头部信息中获取名为"token"的字段，该字段包含用于身份验证的JWT
		String token = request.getHeaders().getFirst("token");

		//4.判断token是否存在
		if (StringUtils.isBlank(token)) {
			//如果token为空，则认为用户未通过身份验证，并终止请求的进一步处理
			response.setStatusCode(HttpStatus.UNAUTHORIZED);
			return response.setComplete();
		}

		//5.判断token是否有效
		try {
			Claims claimsBody = AppJwtUtil.getClaimsBody(token);
			//是否是过期
			int result = AppJwtUtil.verifyToken(claimsBody);
			if (result == 1 || result == 2) {
				response.setStatusCode(HttpStatus.UNAUTHORIZED);
				return response.setComplete();
			}
			//获得token解析后中的用户信息
			Object userId = claimsBody.get("id");
			//在header中添加新的信息
			ServerHttpRequest serverHttpRequest = request.mutate().headers(httpHeaders -> {
				httpHeaders.add("userId", userId + "");
			}).build();
			//重置header
			exchange.mutate().request(serverHttpRequest).build();
		} catch (Exception e) {
			e.printStackTrace();
		}

		//6.放行
		return chain.filter(exchange);
	}

	/**
	 * 优先级设置  值越小  优先级越高
	 *
	 * @return
	 */
	@Override
	public int getOrder() {
		return 0;
	}
}
